Controlling settings, permissions, and membership within Teams and channels
Update your app then
In Teams, go to the channel you want and click Add a tab Add button.
Under Tabs for your team, click Forms.
In the Forms tab configuration page that opens, choose Create a shared form that your team can edit, then provide a name for your new form.
Post to the channel about this tab is automatically checked so you can immediately share your new form with your team. If you don't want to share it right away, deselect this option.
Click Save.