Get On The Air — N3FJP AC Log Other-field titles (ADIF tags)
https://getontheair.app/guide/logging/n3fjp/

The TITLE you type in Settings > Other Field Titles IS the ADIF tag.
"My Park" will not upload. MY_SIG_INFO will.

MINIMUM (N3FJP FAQ two-field)
  Other1  SIG_INFO       Fill: (none)           Hunter / P2P park
  Other2  MY_SIG_INFO    Fill: Previous record  Your park (US-1356)

RECOMMENDED FOUR-FIELD (P2P without hand-editing ADIF)
  Other1  MY_SIG         Fill: Previous record  POTA
  Other2  MY_SIG_INFO    Fill: Previous record  US-1356
  Other3  SIG            Fill: (none)           POTA on P2P only
  Other4  SIG_INFO       Fill: (none)           Their park on P2P only

OPTIONAL if you still have slots and your AC Log vintage exports them
  MY_POTA_REF   comma list for a 2-fer you are activating
  POTA_REF      their parks (list)

AC Log 7.0.10+: force UPPERCASE on these Other fields (POTA naming).

Then:
  Settings > Fill Fields When Tabbing from Call   ON
  Settings > Edit Fields Displayed > Enable Repositioning   OFF when done
  Settings > Setup   = YOUR grid this sitting (MY_GRIDSQUARE)

Official: https://www.n3fjp.com/faq.html
POTA doc: https://docs.pota.app/docs/activator_reference/n3fjp_guide.html
ADIF:     https://adif.org.uk/317/ADIF_317.htm