Master text frames are not all that useful, generally, if you intend the text to be editable. You can Place text from a loaded cursor into an EMPTY master frame on the document page, but the only way to edit text in a master frame on the document page is to first override it by Ctrl (Win) or Cmd (Mac) + Shift + clicking on the frame. Once overridden in this way you will lose the connection to the master page frame for any attributes you subsequently change for that frame.
Thank you for the information.
Can I ask you, is it possible to take a master page I like and make it into a template I like. I know how to reuse an existing master page in other documents but didn't see any information about templates.
Templates INDT are the same as INDD, saved only as INDT and will open a copy instead of the original file.
When it comes to the master: Don't create place holder frames here as you might be used in Quark Xpress. Use the ruler margins and align exactly on them your content. So you will be able to adjust them later via Layout Adjustment.
Exception is the Primary Text frame, which is to recommend with books and mass of text. Less recommended for magazine or flyer layout. (Normal standard way how it is done.)
Master pages themselves can't be a template, but any file in which the master page is used can be a template, just by saving as such. Templates can contain much more information, though, than just master object placement, including styles (very important), color swatches, and multiple pages. You can even have content on the document pages in a template file, and if you are doing placeholder text, it might make more sense to put it on the live document page than it does to put it on a master page.
Master pages are best suited to content that will appear on multiple document pages.
So you mean that the master page should contain content like headers and footers which repeat and line guides, margins, baseline grids from which I can later base my text frames and content frames. Is that right? But I can save a document whose (I don't know what to call it) global content (fonts, colors, text frames) I like as a template. Am I in the ballpark?