Should I put my contact details in the Word header of my resume?

No, it is safer to put your name and contact details in the main body of the page, at the very top. Word headers and footers are stored separately from the main text, and some applicant tracking systems and older parsers do not read them reliably. If the software skips the header, your profile may arrive without a name, email or phone number, and a recruiter has no easy way to reach you.

You rarely know which system an employer uses, so plan for the most cautious one:

• Type your name as the first line of the document body, not inside the header area.
• Put your email, phone, city and LinkedIn link on the next line or two, also in the body.
• Keep the header and footer empty, or use them only for things that do not matter if lost, such as page numbers.

Visually, a top-of-page block in the body looks exactly like a header, so you lose nothing in design. After saving, open the file and copy all the text into a plain text editor. If your name and contact details appear at the top of the pasted text, you are in good shape.