Forcing rhubarb means covering it/excluding light very early on in the year to speed up growth and encourage longer, rosier stalks.
Here's the overview from the BBC Gardener's World site:
Forcing rhubarb by covering the crowns
will encourage the plants to make
early growth. These forced stalks can
be harvested for use in cooking when
they are 20cm - 30cm long and make a
useful substitute for fruit when there
is little else in store from the
It's not essential, and in fact, it's not all that good for the plant. We've enjoyed rhubarb for many years without forcing it, but our crop is less good-looking (greener, stubbier) and possibly a bit more bitter, than a forced crop would be.
In your particular case, where you've inherited the rhubarb, that's the same as us. It takes practically no looking after. Even if you try and damage it, it's pretty good at recovering. In my ignorant first winter I thought the roots were some kind of tree root and I hacked away at most of my crop. Came back superbly the next Spring.