en_tn_condensed/phm/01/02.md

Philemon, our dear friend ... Apphia our sister ... Archippus our fellow soldier

The word "our" here refers to Paul and those with him but not to the reader. (See: rc://en/ta/man/translate/figs-exclusive)

Apphia our sister

Here "sister" means she was a believer, and not a relative. Alternate translation: "Apphia our fellow believer" or "Apphia our spiritual sister" (See: rc://en/ta/man/translate/translate-names)

Archippus

This is the name of a man in the church with Philemon. (See: rc://en/ta/man/translate/translate-names)

our fellow soldier

Paul speaks here of Archippus as if they were both soldiers in an army. He means that Archippus works hard, as Paul himself works hard, to spread the gospel. Alternate translation: "our fellow spiritual warrior" or "who also fights the spiritual battle with us" (See: rc://en/ta/man/translate/figs-metaphor)