By intuition, I would say that after writing an acronym, one need not capitalize the first word after it. However, after seeing how writing-software capitalizes any word which follows the acronym, doubt surged.
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Your question is not very clear, but as I understood it, you're talking about the software auto-capitalizing words after dots.
Most text-editing software capitalises the word right after the acronym because it's written with dots like T.H.I.S. and like I said above, since it auto-capitalises words after dots — in case of a typo, for example — it also does it in this case.
But speaking about English, an acronym — although it might have dots — works like any other word inside a sentence. If I were to write an acronym like I did above, the word after it would stay lowercase, because those dots don't signal the end of a sentence, but rather the acronym's structure.