By default, your participants can only respond once per device.
If you have a Pro, Conference or Enterprise subscription, you can turn on the ability to have your audience respond several times from one device in your presentation settings. This is only available for presentations set to Survey mode, where users can answer your presentation in their own time.
To allow your audience to respond several times per device:
Go to you Mentimeter presentation in the Editor view.
Clicking on the gear icon in the top left corner to open the Settings menu.
Select Survey under Type of Menti
Toggle "Multiple submissions per device"
Open Ended Questions and Word Cloud
For Open Ended and Word Cloud, for all plan types, you can give your participants the option to submit responses more than once. In the edit screen, click on the response section of the slide, then turn on 'Multiple responses per person' in the panel on the right:
When you have activated that feature, your participants will receive a prompt to submit more answers after they send in their first response for Open Ended or Word Cloud: