Learn Dutch: Zij heeft de map gewist. - She has deleted the folder.

No, map is a false friend. In Dutch, map means folder (like a physical file folder or a computer folder). If you want to talk about a geographical map, you should use the word kaart.

Why is the past participle gewist spelled with a t at the end instead of a d?

The infinitive verb is wissen (to delete or erase). To make the past participle, we look at the stem, which is wis. Because the stem ends in s (one of the consonants in the 't kofschip rule), we add a t to make gewist.

Why is gewist placed at the very end of the sentence?

In Dutch, when you use a perfect tense like the present perfect, the helper verb (heeft) takes the second position in the sentence, but the past participle (gewist) gets pushed all the way to the end.

Could I say Ze heeft de map gewist instead of Zij heeft de map gewist?

Yes, absolutely! Ze is the unstressed version of zij and is actually more common in everyday speech. You would use zij here only if you want to emphasize exactly who deleted the folder (meaning she did it, not someone else).