How could cover a telephone plate

Not sure if you are looking to decorate it or completely hide it. You can always paint or cover with contact paper.

Here is a link that will give you tons of ideas. Hope that helps!

https://www.google.com/search?q=covering+a+phone+jack&rlz=1C1BLWB_enUS700US700&source=lnms&tbm=isch&sa=X&ved=0ahUKEwiuvd2Al7TWAhUKTSYKHQKxBzgQ_AUIDCgD&biw=1024&bih=714

Hi Tammy. If the phone line is no longer hooked up you can remove it. I have done this and it looks so much better. I purchased a small piece of drywall from a hardware store to fill the hole. You will want to take a few shims and put them in the empty hole. Then while holding them try to get a screw through the dry wall and into the shim. You may want to predrill into the drywall. This can be tricky so be patient. I then cut a piece of the drywall as close as I can to the size of the hole. Then screw the drywall into the shims. Then take drywall compound and fill in the gaps trying to blend it well. Once it is dry you will need to sand. After the first sanding you may need to add another coat of the drywall compound, and repeat sanding. You want to blend it as good as you can. Then prime and paint the area.

It would be much simpler to put your creativity to work and paint it in a design that matches the decor in the room it is located.

I have one of the old phones hanging by mine. I was found an old telephone book and hung it over the plate.

I did embroidery of Home Sweet Home and attached it with a small nail over the hole. If you don't embroider, hang a small or size of hole picture. Easy fix.

They are paintable.

A picture or anything decorative

hang a picture of piece of art work over it

Take it off and contact paper it. Spray paint it with Krylone plastic paint.