One common challenge is finding enough time to workout every day. It's not that you don't have 30 or 60 minutes free during the day, but having it consecutively, every day, in a place where you can exercise and then get back to what you are doing - that can be a challenge.
One way to get a little exercise and to start the day off right is to just do a quick "workout" session first thing in the morning. Or, barring that, last thing before bed. You don't need a gym, or any equipment (aside from a pullup bar, for one of the options.)
Before breakfast, before you shower, before you do anything else, just get in one short movement session every day.
Here are six workouts. If you have trouble picking one, just roll a die. Or do a different one each day, it doesn't matter.
1) Bodyweight Squats - Do one set of squats, aiming for at least 25 reps, and aim to work up to 100 (it won't take 5 minutes.) Don't go for speed, but for form and pace. A good way to do this is to find a chair, hassock, or box that is slightly below parallel. That's where the crease of your hips lines up with the crease of your knees (or, if that's hard to gauge, aim for the top of your thigh being parallel to the floor.) Don't rush, just get them in.
More advanced: Deeper squats, with a weight, or paused at the bottom.
Less advanced: Shallower squats, holding on to a stick, countertop, or railing.
2) Pushups - Do one set. Do 1/2 as many as you could do in a single set to failure. If your best is 20 pushups, do 10. Best is 4, do 2.
The goal is to get the easy reps, and just get them in.
More advanced: Feet on a box.
Less advanced: Pushups off of stairs (hands on steps) or a counter.
3) Step-Ups - Find a box (or a staircase) that is about knee height. Do at least 25 step-ups per side, one leg at a time.
More advanced: Add weight.
Less advanced: Alternate legs.
4) Plank Series - You need a stopwatch for this. Do one plank, aiming for 60 seconds, but stop before then if you can't hold proper position. Then do a side plank, one on each side, for half of that time. Then do the regular plank again. The goal is 60s/30s per side/60s, with no breaks - 3 minutes total.
More advanced: One-legged planks, arm extended and leg lifted side planks, shoulder-touch planks, plank to pushup.
Less advanced: Shorter times.
5) Pullups - Do one set. Do 1/2 as many as you could in a single set to failure, just like with pushups.
More advanced: Add weight.
Less advanced: Do body rows, instead.
6) Pick any two, and do half as much of each. If that's too easy, do one full set of each.
Just wake up, knock off the reps, and then get on with your day.
Aren't these too easy? Yes and no. On one hand, yes, this is too short, not intense enough. But the point isn't to get in a maximally effective or even optimally effective workout, but to get in some exercise. It's building a habit of getting up and moving. It's not like doing some squats, pushups, or a plank is going to be a negative. And it's going to make those movements more effective and efficient over time. Doing something every day will make it easier to keep exercising, and make moving easier and more effective.
Can I do something else instead? Of course. Knock off a set of kettlebell swings. Do a set of goblet squats. Do ball slams (not recommended if others are sleeping). The goal is short, easy to do, low equipment, and effectively "painless" exercise to get in the habit.
This is fun, can I do more? Yes, but it's probably better to space it out. Do one quick one in the morning, another one at night.
One Final Tip - One recommendation I've given some clients is "squats before snacks." You can have a snack, but before you do, you need to knock off 10 bodyweight squats. That's it - just 10, and you can have that snack. It's not like 10 squats negates the effect of an unhealthy snack, but rather it both serves to remind you of what habits you really want (squatting, not snacking), and potentially substitutes one for another. And at worst, if you do you squats and then eat the candy bar anyway, you took one step forward along with your steps back, which is better than just the steps back. So you can try this, too - do one workout in the morning, and then pick one to do before cheat meals or snacks. Stick to it for two weeks, and see if it doesn't make movement stick as part of your life.