You can currently choose fonts available in the Prezi library via the advanced Theme Wizard. Please see this article for the steps you need to take.
All other fonts are officially unsupported by Prezi.
If you have a specific font that you would like to use, it is possible to use fonts that are not within the Prezi library. However, this will require payment. For all matters regarding the use of fonts not within the Prezi library, please contact our Sales team by filling out this form.
You can also search the forum for officially not supported workarounds concerning this issue.
If the information above didn't answer your question, please open a new topic and post your question there.
All other fonts are officially unsupported by Prezi.
If you have a specific font that you would like to use, it is possible to use fonts that are not within the Prezi library. However, this will require payment. For all matters regarding the use of fonts not within the Prezi library, please contact our Sales team by filling out this form.
You can also search the forum for officially not supported workarounds concerning this issue.
If the information above didn't answer your question, please open a new topic and post your question there.