Help action help

[dnd2016]

Do i have to be in 5ft of my ally or the foe? Can i use help action with an ally within 5ft of me, against a foe 40 ft away?

[Demonslayer666]

When aiding in their attack, you have to be within 5' of the creature.

When aiding in an ability check, it doesn't specify how close you must be, so this will be heavily dependent on your DM and the task at hand.

[nickl_2000]

The only case where this isn't true is the rogue archetype mastermind ability master of tactics. This is a 3rd level ability from SCAG and let's you help as a bonus action from 30ft away