Views Add Button

Simple module that allows you to make, in the header or footer of a view, a link to add content of a particular entity (eg, content type)

In the header you can find a new item:

You configure what you want to add.

You should also apply the rights you want.

If you have the appropriate rights, you see the link. Otherwise is it not visible.

You can transform the link via CSS to a button. You get plenty of tools  ...