"S" after always

Is it accepted to add “s” to any verb that follows “always” in a sentence?. For instance: John always tell’s’ the truth. Or I should put it in the past like: John always told the truth. Which one stands. Thanks

Not a teacher.

Yes, you should add “s” in Present Indefinite sentences.

He always plays cricket.
She always takes tea in the morning.

Not in Past Indefinite sentences.

He always spoke the truth.
She always told a lie.

John always tells the truth - no apostrophe.

The form of the verb is dictated by the tense and subject, and has nothing to do with the presence or absence of the adverb “always”.

John tells the truth / John always tells the truth
John told the truth / John always told the truth
They tell the truth / They always tell the truth
They told the truth / They always told the truth

By the way, apropos of Beeesneees’ comment, I suspect that you wrote tell’s’ in order to highlight the letter ‘s’. I recommend that you do not put quotes around individual letters in a word – it is too confusing. If you want to highlight individual letters in a word then you can use bold; for example, “tells”.