Hello, I'm new in this site and I posted my first pic, but when I put the artist name into the tags it's put among the general informations and not undrer the voice "artist", I also tried to write "BuickSkylark_(artist)", in order to specify that was the artist name and not a general tag.
How can I do to make this tag result as artist name?

If you're making a completely new tag (a tag that has never been created before), you need to add artist: before the tag to change it to an artist tag. If it already exists or if you just created it without setting a type before first use, then you need to go to the tag index, search for your tag specifically or partially with a wildcard (in this case, buick*), click "edit" next to the tag type for the tag you want to change, and then select the type from dropdown list and click "Save".

I've already changed the tag type for all three for you. I've removed the tags with the _(artist) disambiguation from the post, however, since there are no other tags with your name.