Application is free, but authorization is subject to conditions.
If you only apply for a pattern, you will not be granted a patent right.
You can apply for wallpaper with this pattern and apply for a "design" patent. Wallpaper is a flat product and can be granted a patent.
If you have time, it is recommended that you go to the official website of the "State Intellectual Property Office" to search for the patent authorization disclosure text related to "wallpaper" or "wallpaper". For reference, it may be useful for your patent application. help.
If you are not very tight on funds, it is recommended that you entrust a regular patent agency to handle matters related to patent application, so as to ensure authorization.
I wish you success in applying for a patent.