If you have the appropriate AutoFormat As You Type option enabled, it should
happen automatically, but you can manually select the th and press
Ctrl+Shift+= or use Format | Font | Superscript.

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Suzanne S. Barnhill
Microsoft MVP (Word)
Words into Type
Fairhope, Alabama USA
Word MVP FAQ site: http://word.mvps.org
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> how do i write "th" in the upper right corner of "5th feb" instead of writing
> it right besides 5?