how to look for spaces?

Hello

I am creating a small function that should create a new login for future users. The login is 7 characters long. Spaces in that name (in cell A1 eg) should be removed? But how do I do this?
How do I remove the space in the name: "De Castro Imelda". Apparently the function TRIM does not help me much. Either I use the wrong function, or I my syntax is not good...

Many thanks for your advice.