closing a hole in a plane

I have noticed that its easy to extrude a plane while holding down CTRL and click.
But how can you close a hole or insert a face without having double lines.

You can create a face by selecting 3 or 4 verts and hitting the “F” key to create a face,
and you can merge verts by selecting as many as you want and hitting alt/option & “M” to merge

Thanks of course the F from Face.
Is this also possible with edges.

yes, it is

Thanks for this thread … it helped me too (newbie)

Thay is what we are here for,
right midgetmike?

If there is a hole in the mesh surrounded by a continuous loop of edges or faces, with 5 or more surrounding vertices, you can fill the hole with faces by pressing Shift-F, then Alt-F to improve the layout of triangular faces, then Alt-J to convert the trie’s to quad’s.