StringPadLeft

StringPadLeft["string",n] makes string be of length n, padding it on the left with spaces or truncating it if necessary. 

StringPadLeft["string",n,"padding"] pads by repeating copies of the string padding.

StringPadLeft[{s1,s2,…}] pads strings with spaces on the left to make them all the same length.

StringPadLeft[{s1,s2,…},n,…] pads or truncates to make all strings of length n.

Please visit the official Wolfram Language Reference for more details and examples on core symbols.