A right-to-sue letter is essentially granting you permission to file a lawsuit in court. When you first make a complaint to the DFEH or EEOC, they will investigate your claim if you would like them to. At the end of the investigation, they may file a lawsuit on your behalf if they believe it is warranted.
If your goal is to file a lawsuit in court, you want to hire an attorney and then request that the DFEH or EEOC immediately issue a right-to-sue notice. You won't be able to file an age discrimination lawsuit in court until you receive this notice. You should make sure you have an attorney before you request your right-to-sue notice because of the short amount of time you’re given to file the lawsuit once you receive the notice. As stated above, in some circumstances, you’ll only have 90 days to file a lawsuit from the date you receive this notice. If you don't already have an attorney, it can be quite challenging to find the right lawyer or firm and get them to initiate that lawsuit in such a short period of time.