The display of nonprinting marks is specific to each Word user (each Word installation). This isn't something that is controlled by the document or stored within the document itself. (Confusingly, it is possible to temporarily change the setting for just one document window. The setting which is active when you exit the last Word window in a session will determine the status of nonprinting marks the next time you start Word.)

In the Word Options dialog box, clear all check marks for nonprinting characters, including the "All" option. This will hide the nonprinting marks but not delete any of them.

Tab characters can be deleted the same way as you can delete other content.

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Stefan Blom
Microsoft Word MVP

Microsoft 365 apps for business
Windows 11 Professional