Head coverings in ID cards are typically allowed in countries where individuals wear them for religious or cultural reasons. In some countries, head coverings such as hijabs or turbans are permitted, but only if they do not obscure the applicant’s facial features, meaning the face should be fully visible from the forehead to the chin (eyes, nose, and mouth) without any shadow. Similarly, if a hat is allowed, the face visibility requirements are the same.
Just a heads up - it’s very important to double-check the specific regulations for the country in which you’re getting your document issued.