Vona, Butcher of Magan

• WOTC Official Reminder Textofficial rules
  Lifelink — Damage dealt by this creature also causes you to gain that much life.
• WOTC Official Reminder Textofficial rules
  Vigilance — Attacking doesn't cause this creature to tap.

• WWizards of the Coast2017-09-29
  Official Ruling
  Vona's last ability can be activated during any step or phase of your turn, including the combat phase. It's possible to attack with Vona and then activate its ability before blockers are declared. Doing so won't remove Vona from combat.

Rulings via Scryfall