To add collaborators to an existing Microsoft Forms form:

1. Log in to your Microsoft account and open the form you wish to add collaborators to.
2. Click the Share icon in the upper-right corner of the form.
3. Type the name or the email address of the person who you'd like to share the form with.
4. Choose the level of access you’d like to give them and click the Share button.
5. Repeat this process for each person you want to add to the form.