It can be hard to get exercise in when you have a desk job. Here are some tips and links to help you add little bits of movement and strength training to your work day. Exercise is cumulative, so those little bits can really add up!
If possible every hour walk around the office or up and down a hallway, maybe take a flight of stairs for a little extra umph.
Desk Squats - Stand in front of your desk chair and start to sit down, but stop just as your fanny comes near the chair and stand back up. Repeat 10 times. Make sure you are far away from your chair that your knees do not go over your toes.
Try doing pushups off of the side of your desk or the floor near your desk or try to do a few planks throughout the day.
Here are some links to more ideas
Yoga for the office - https://www.yogajournal.com/practice/beginners/how-to/office-yoga