How to change the post meta line

I would like to change the meta line of a post.
I would like to display the update time rather than the post time.
I might whant to hide the user that did the post, as I will only have one user doing posts.

I have managed to change the category button to a text link.

The ultimate solution is to be able to design the meta line all on my own.
How can I do this with as little inpact on the original theme?
I have made a child theme.

The link to my testsite is https://f01.joodit.com