Yes. Set Device requirements on your study's Recruit tab. The options are Any device, Mobile only or Desktop only.
How it's enforced
The requirement is shown to participants when they apply, and the platform typically detects the device used for unmoderated tasks. For example, with desktop only selected, participants are directed to open the task on a desktop even if they applied on their phone.
What about cameras and microphones?
Studies that record require camera and microphone access, and participants agree to this during their application. For moderated sessions, it's still worth a belt-and-braces reminder:
Add a screener question reminding participants they'll need their camera on and be speaking out loud.
Send a message before the session restating the device and setup requirements.
You can control what's recorded from your study's ⋯ menu under Recording settings.
What about tablets and unusual devices?
Tablets such as iPads sit outside the simple mobile/desktop split, so if a specific device matters to your test, say so explicitly in a screener question and ask participants to do a quick tech check before their session.
Does Askable Sessions work on mobile?
Yes. Participants can join from the Askable app on the App Store or Play Store.