What do you call a person without whom work does not get done? [closed]

An irreplaceable person, in the context of getting work done.

Is there a word to describe such a person?

Solution 1:

I think the word you're looking for is:

• linchpin (Cambridge Dictionary)

the most important member of a group or part of a system, that holds together the other members or parts or makes it possible for them to operate as intended

You might also use :

• key player (Cambridge Dictionary)

an important person, company, etc. in a particular area of activity:

Solution 2:

Maybe:

• Indispensable (Cambridge Dictionary)

Something or someone that is indispensable is so good or important that you could not manage without it, him, or her:

His long experience at the United Nations makes him indispensable to the talks.