Depends on the fern. Most indoor ferns do not produce 'branches' or side
shoots that could be used as a cutting, though several will form a clump
with multiple crowns, or have branched underground or creeping rhizomes,
that can be divided. A frond on its own will not be any use unless it one
of the small number of ferns that can produce plantlets from its fronds.
So, first you really need to identify the fern, and if it can be divided
you have to figure it dare to try.
all the best,
> My mother has a beautiful indoor fern, which she has had for some
> years. I have taken cuttings on several occasions, but they never seem
> to take.
> Any advice please?