You can use the StringRightPad action in the Community Commons module in the Marketplace to pad a string to the right.

It takes 3 parameters

1. The String you want to pad
2. The amount you want to pad by, e.g 10 if you want your string to be padded to at least 10 characters
3. The character you want to use to pad the string out with, e.g. ‘ ‘

It will return a new String variable that you can then use in your application. If the string you pass in is longer the amount you want to pad by, no padding will take place.

I hope this helps.