Using the Selection tool, select
a frame, or using the Type tool, click inside the text frame or select
text.
Choose Object > Text Frame Options.
In the Inset Spacing section on the General tab, type
the offset distances you want for Top, Left, Bottom, and Right.
(Click the Make All Settings The Same icon to
use the same spacing on all sides.)
If the frame you’ve selected has a non-rectangular shape,
the Top, Left, Bottom, and Right options are dimmed, and an Inset
option is available instead.