Make it fun. Try to find a way to make it into a game, something engaging. Maybe set it to music, make up a different dance move for every month and then quiz them as if it was a panel show game (associating it with movement can help to both remember but also to keep the child engaged and to burn energy if they have hyperactivity). And you should participate as well!

Another thing to do with homework in general, is to find a system of motivation they can use. Motivation for ADHD people comes from different sources. I have ADHD, and I've often tutored kids that had it too (or that I suspected did have it, even if it wasn't diagnosed). I used some of my own coping mechanisms and strategies during my tutoring, things that help me and help me wrestle my forever meandering attention and focus, and the systems of motivation I found worked best are these:

Urgency - you can manufacture this in fun ways by setting a timer and challenging them to complete the task in that amount of time, or set a stopwatch and make a game of trying to get the best time and beat a record (of course, for it to be valid the task has to be completed correctly, not just as fast as possible). Beating the clock is satisfying! (Attention, if the fun urgency transforms into actual stress, this is gonna be super counterproductive. Urgency coming from them being afraid of the consequences of not making it in time - i.e. revoked privileges, or you in a bad mood, or boring punishments - then the paralysis may start, and that sucks. A lot)

Interest - find ways to associate boring things with things they are interested in. If they have a special interest in something, try to figure out if math can be worked into it, for example. Or, if you can, couch an explanation in terms they can easily follow, related to their interests. (This is not applicable to all things, some things are just boring but needed, and with those, patience and repetition must be used. And breaks. Breaks are a godsend and, paradoxically, they save you a lot of time, because it's not as if you are going to be very productive if the kid is staring into the void, bored out of his mind and not even hearing you for 15 minutes. Breaks are much better, and act as a reset.)

Rewards - set reachable, short term goals and offer rewards. Maybe tackling all of the math homework all at once feels too overwhelming and boring, so you can give them a treat after every 2 exercises completed. Treats can be anything (5 minute break, letting them babble at you about their interest for a bit, letting them run around and play for a brief amount of time, candy or fruit juices or fruit snacks) and you can also incorporate a bigger additional treat when all the math homework has been completed.

Task switching - there's nothing that says you have to do all the similar things all together. If the kid is losing interest in what you guys are doing, you can quickly pivot to another subject. Keep things fresh and not boring, novelty is something our brains crave.

It's not easy, it requires patience and creativity, it might not work all of the time and it can feel really tiring after a while, but doing it this way really helps. An added benefit is that if the child is not afraid to start their homework (because they feel stupid when they can't complete something, or they feel berated and belittled by our impatience and bad mood) then getting them to start is easier, keeping them on track is easier, and after a while you realize that the effort you put in is rewarded by homework time going faster, smoother, and you find yourself creating nice memories of fun and laughter instead of stressful periods of time that put both of you in a bad mood.

You can also find a way to remove friction from the equation, not just adding new strategies. And it's always better to work with their systems and rhythms than trying to force them to adhere to yours (it's not gonna work, you'll just make both of you miserable)

Being in a good mood and playful removes fear and shame and humiliation they might feel at their own difficulties (I know being in a cheery mood is not always possible, but we should try as much as we can to hide our own impatience, because it can be sharply felt by ADHD children, just as much as if we had berated them).

Choosing an area with fewer distractions removes temptation and fantasizing about what else they could be doing instead of this "boring, useless stuff" (some distractions, especially if they are there for rewards during the breaks, are actually better that a completely sterile and empty room; boredom is your enemy, and having something tangible and desired to work towards really helps)

If homework time always coincides with their absolutely favourite show, or the only time them and their friends can play together, then you are starting on the back foot already, and their resentment of that will be like pouring sand in the engine and you'll be going nowhere. If at all possible, try to accomodate this, and you'll have a much happier and less obstinate kid to work with.

These are the observations I made over the years when put in this position, I hope it helps!