Hi, and welcome to the forum.
No. Welcome, by itself, means something else.
Someone comes to your door and rings the bell. You open the door and see someone you are expecting and like. You say,
"Welcome. Please come in. I'm so glad to see you."
Doormats are little 'carpets' that people put outside their front door for people to wipe their shoes on. They often have "Welcome" printed on them.
Again, Welcome.