Autocorrect using subscripts

[Guineapic]

I want to set up, using "autocorrect", H2O to H-subscript 2-O. Can this be
done? or is there a way to change this with Find & Replace??

 

[SVC]

Create your H2O as you want it to appear and highlight it.

Tools > AutoCorrect. be sure Replace text as you type is checked.

H2O should appear in the "Replace" column. Click on "Formatted Text" above
the "With" column and the formatted version should appear. Then click OK.

Now type H2O plus a space and you should get your formula

Type