How can I enlarge or reduce a lettertype and save it that way so it stays in that size?
I use Windows 10.

Thank you !

Are you referring to the font in an application, like Microsoft Word? If that's the case, there is usually a setting in that particular program where you can set the default font, font size and style. Look it up in your program's help, which is usually found as the last link in the menu bar of the program.

No, it's not really that. When I go to settings, personal settings, fonts, than I can see all the fonts that are downloaded on my computer. When I click on the font, I can see the fontsize. There I can change the fontsize, but there is no confirmation button. When I return to the previous page, I see that the size is not changed. The result of that is, when I change the fontsize in a document (Word or Excell), the computer sees that apparently as a new font. Because the dowloads of fonts is limited, I can not further download other fonts. even that I'm not over the limited number. I hope you understand what I mean because my english is not that good

See if this would help

https://support.microsoft.com/en-us/office/change-the-default-font-in-word-2f50603b-9886-47e4-a483-48ac5ab80163

Thanks for the answer, but that's not really what I'm looking for. I know how to adjust a font in a Word or Excel document and possibly save it for subsequent documents. I downloaded a number of fonts and made a list in Excel, so an overview of all downloaded fonts, in the font as the font is called. But if I want to enlarge or reduce the font in the Excel list, it is not accepted because the maximum number of fonts has been reached, because enlarging or reducing that font is apparently regarded as a new font. If I could confirm the size of the font in the personal settings, I think this would be solved, but I can't. I understand that this may be difficult to understand, but I can't really explain it any other way.

Excel specifications and limits

Unique font types: 1,024 global fonts available for use; 512 per workbook

https://support.microsoft.com/en-us/office/excel-specifications-and-limits-1672b34d-7043-467e-8e27-269d656771c3