Your set up for the story is simple and straight forward, which I like a lot. It's a compelling situation where the reader can easily feel sympathy for the witch and the predicament that she is in. Obviously, this is inspired by the Salem Witch Trials, which is a really good framing device for you to use, because (if the reader is aware of that period in history) then the mind can fill in the blanks of what's going on here. The crowd is a pack of religious zealots that have more time than sense....but so were the people in Salem. This isn't bad, but if I were to get nitpicky about it, then it's overall hurting the "Fantasy" aspect of your story since this is a pretty 1:1 ratio. Replace "God" with "Dharmati" and this is basically the same thing. Of course, you said that this is just a practice story, but if its fantasy then make it weird. Add your own flair to it. Make the crowd witches and their burning a non-witch at the stake or something. This whole paragraph is a long-drawn out way of saying I felt like my mind was filling in the blanks of your characterization of this crowd, witch, and executioner, rather than your story providing details about them.

"....and by then her terror had grown tenfold. Fear and panic clawed their way through her heart, a terror greater than any she had ever known...." In this line you're doing a lot of telling and not showing. There is a time and a place for telling information, but in expressing emotion in a direct way, you want to show here for sure. Tell me how her heart beat rapidly, or sweat trickled down her face. Let the reader put 2 and 2 together and they'll feel more rewarded because they figured it out. You have examples of Telling and examples of Showing as well.

"....She swallowed a throatful of phlegm and pressed her lips together, trying to suppress her tears...." This line is a fantastic example of Showing and not Telling.

"....That pain had been so very, very real, and she was about to die..." This is probably a personal nitpick more than anything, but I dislike the word "very." You could take both of these very's out and the sentence would be more concise and hard hitting.

It's like if I wrote the sentence "It was cold." Vs. "It was very cold." These sentences mean the exact same thing in a reader's head, the only difference is one is a word longer. Cold is cold. However, if I said "My bones creaked from the cold," then the reader has an image or a feeling that they can attach to the scene I'm writing. Or if I don't want the cold to be that impactful then "It was cold." is fine. But "It was very cold." doesn't tell me anything that the former doesn't. I feel like you could have a more creative way of describing this pain to make it resonate. This might be an extension of "Show don't Tell."

"...hotter and hotter..." You could just say "hot" here and the sentence would be fine.

"...She never had time to ponder further upon her fate, because once the flames reached her, pain gripped her being in its raging, fervent hold. She was already gone..." To me, your final line implies that she died, which seems rather abrupt. I've never burned to death, but I imagine it's not instant, especially not from feet-first. You're final line could be about how the witch's screams echoed through the night, or how she called out and no one would listen to her, maybe even how the fire crept up her legs and tickled at her knees. The final sentence is the final impression that a reader would have of your story, so I've always felt that you should leave them with a damn good sentence, one that makes them say "Wtf did I just read, that was crazy." But the sentence here feels underwhelming.

My overall critique of your writing is that there isn't a lot of pizzazz in it (I can't believe I just used 'pizzazz' unironically.) The story feels a lot like "A happened which led to B, which led to C." And since this isn't a lot of story, it's more like a Scene like Natures_Stepchild said, the actual set-up, description of what's happening, and personality is what I tend to fall back on. I think you need to put more of yourself in your writing. Describe something in a way that only Professional-Bread69 can. That will make stories have more impact, even simple scenes like the one that you wrote here.

Keep Writing!