Hello,
Thanks for getting in touch.
I'm sorry to hear that you're having this problem. I'd like to learn more about your setup so we can figure out what's going on. First, can you kindly tell me what kind of account you have? Is it a personal account (like Hotmail or Outlook.com) or a work or school account managed through Microsoft 365 Business or Education? This is important since the features that are provided can change based on the subscription.
In the meantime, you can take a few actions to fix the problem. When you share, be sure to choose Screen instead of Window. Annotations don't work when you only share one window. You should also make sure that Teams is fully up to date by clicking the three dots next to your profile and choosing Check for updates. This is because updates that are still pending can change the availability of features. If the problem keeps happening, clearing the Teams cache could help refresh the software and bring back missing options by getting rid of old or broken temporary files.
I hope to hear from you.
Thanks,