PowerPoint supports a feature called TrueType Font Embedding. If you have this turned on in a slide deck, all embeddable fonts are included as part of the .pptx file. This means that, theoretically, if you open that deck on a different computer that doesn't have the same fonts installed, all the text will appear correctly. This technology is different from the font embedding used in PDF documents, so many fonts that can be embedded in a PDF can't be embedded in a PowerPoint file. If you are designing a deck and you will have control of its distribution, font embedding is a useful and powerful tool. However, if you are designing a template or a deck that will be distributed for others to edit, it can cause problems for those uses.
Issue #1: Not all fonts can be embedded. TrueType (*.ttf) and OpenType (*oft) fonts have an internal code that determines if those fonts are embeddable, embeddable read-only, or non-embeddable. PowerPoint will only embed those fonts that are TrueType or OpenType and are marked as embeddable or embeddable read-only.
Issue #2: Fonts say they are embedded but still display incorrectly. Sometimes a font will be coded to be embeddable, and the embedding process seems to go OK. However, when you open the file on a machine that doesn't have those fonts the text displays as Calibri, Arial, or Times New Roman even though it says it's in the correct font. In this case, there isn't really anything you can do. To check for this issue, before you distribute your template, try opening it on a machine that does not have those fonts installed.
Issue #3: Read-only embedded fonts. If you open a deck that includes fonts that are embeddable read-only, you will receive this warning: This presentation cannot be edited because it contains one or more read-only embedded (restricted) fonts. To edit the presentation, you must remove the restricted fonts, or you can open the presentation as read-only. There are two buttons: Open Read-Only and Remove Restricted Fonts. You should also check for this issue before you distribute your template by opening it on a machine without those fonts.
Issue #4: Font errors saving a deck. If you create a new deck based on a template that has embedded fonts, when you save it, PowerPoint will try to embed all the fonts that the slides use, not just the ones that are part of the template, and you might get this error: Some of your fonts cannot be saved with the presentation. This is followed by a list of the fonts and the reason each font can’t be embedded. That reason might be “Font Not Available”, “Restricted”, or “Not TrueType.” This error is caused when you paste in information from an outside application, such as a web page or another presentation. That content might try to use additional (non-template) fonts which are unavailable for embedding. These errors are annoying but can often be ignored. Just open the slides on a different machine and make sure everything looks OK. In many cases, you can use the Replace Fonts command to substitute the problem fonts with others.
Notes:
1. To turn font embedding on or off:
(Windows) Click File and then click Options on the sidebar. In the PowerPoint Options dialog box, click Save on the sidebar. Enable (or disable) the Embed fonts in the file check box. Choose the radio button that best represents your use case: Embed only the characters used in the presentation or Embed all
characters.
(Mac) Click PowerPoint and then Preferences. In the Output and Sharing section of the PowerPoint preferences dialog box, click the Save icon. Enable (or disable) the Embed fonts in the file check box and then choose the option you want.
2. To use the Replace Fonts command:
Go to the Home tab and look in the Editing group. Click the down arrow next to Replace and choose Replace Fonts. On the Mac, you can also click Edit and then Replace Fonts. In the Replace dropdown list, choose the font that is giving the error. From the With dropdown list, choose a template font or a standard font (like Arial or Calibri). Then click Replace. The dialog box doesn't go away until you click Close.