"\t" within your computation will create a tab character. For example:

"Col 1\tCol 2\tCol 3"

will produce:

Col 1 Col 2 Col 3
This works very well for creating simple, makeshift tables of variables. For example, the text string "«Var1»\t«Var2»\t«Var3»" will produce:

«Var1» «Var2» «Var3»
For an example of how this technique can be used with a REPEAT, see Computation 18: Column-Style Repeat in a Computation.

See also Computation 12: Returns in Text Strings.