Welcome!

Welcome!- (meaning: we are delighted to receive you) - byenveni!

You're welcome - (meaning: don't mention it, no thanks needed) - padekwa

example: 
1.
Welcome to my home - byenveni lakay mwen
Welcome to our country - byenveni nan peyi nou

2.
Joe:      Thank you for coming (mèsi pou vizit ou)
Marc:   You're welcome (padekwa)
Joe:      Thank you for your help (mèsi pou èd ou)
Marc:   You're welcome, it was my pleasure (Padekwa, se te tout plezi mwen)