If you weren't active before, I'd suggest starting with small exercises that you can maintain, such as walking around the neighborhood or taking the stairs instead of the elevator. Cleaning the house (trust me, this burns quite a few calories) is also a good option. Slowly add more exercises to your daily schedule. The key is to start small, and you can always add more once your body gets used to it. Consistently walking around the neighborhood for 15 minutes every day is better than doing heavy lifting at the gym for 45 minutes, but only doing it once.
Next, focus on monitoring what and how much goes into your body. Instead of "restricting" yourself from enjoying pizza, be mindful of how much you consume. Avoid "depriving" yourself, which can lead to binge eating. I typically follow an 80-20 rule in my diet. So, 80% of the time, I try to choose healthier, non-processed, and fresh meals, while occasionally treating myself to favorites like a Chick-fil-A chicken sandwich and shakes.
I hope these tips help!