Hello,
Would someone instruct me please about the "Iteration" in the Options of
Tools menu. Please tell me the complete steps to use Iteration option. ...
Thanks.

Would someone instruct me please about the "Iteration" in the Options
of Tools menu. Please tell me the complete steps to use Iteration
option. ... Thanks.

Iteration is a way to solve a problem approximately, by repeatedly stepping
closer and closer to the answer. Excel uses iteration when you invoke:
Tools Goal Seek

When iteration works, you can get as close as desired (within Excel's
precision limitations) by taking enough steps. Be aware, though, that
iteration isn't guaranteed to converge to an answer. It depends on the
problem, on the type of iteration method, and on the initial guess. Excel
gives a warning if Goal Seek doesn't converge.

Usually, iteration continues until either (a) the software takes a maximum
number of steps, or (b) the difference between successive steps is small.

If you want to control the "maximum number of steps" in (a), or the
"difference between successive steps" in (b), you can use the "Iteration"
section of the "Options."

For most problems, the default values that Excel provides are good enough,
and there's no need to change the Iteration option. If you have a problem
where the default values don't work, please provide details of what goes
wrong.