"Would you like to come in?" is enough. However, if your friend is on the way to doing other errands, for example, you may want to add "first" to mean "before continuing with your other activities". "I have a lot of things to do today." "Would you like to come in first? -- and then continue with other things?" Also, if several friends wish to come in, and you select one
I was not aware of the other post. It seems I've duplicated quite a bit of what has already been said. Oh, well! A little repetition of a point might help!