Do not make the word or phrase that you want to emphasize the object of a preposition. The object of the preposition is generally considered a weak position in a sentence. Readers pay more attention to the main sequence of subject–verb–object.

There is no rule against ending a sentence with a preposition. The preposition should go where it makes the sentence easiest to read. Like other editorial decisions, the placement of a preposition depends on the rhetorical situation.

Microsoft style

Type the text that you want to search for.

Type the text for which you want to search. (More formal, but also correct.)

Do not join more than two prepositional phrases unless you have no other choice. Long chains of prepositional phrases are difficult to read and easy to misinterpret.

Microsoft style

In the lower-right corner of the Save As dialog box, click Options.

Not Microsoft style

In the lower part of the right side of the Save As dialog box, click Options.

For more information about specific prepositions, see the individual entries in the Microsoft Manual of Style.