How do you remove shifter being stuck at park for a 1990 toyota camry?

For the short term and as a temporary measure, the shift lever can be released by depressing shift lock override button which is in a small hole next to the shifter, typically covered with a small piece of plastic.

A permanent fix is needed though. The transmission shifter has a safety interlock. You must depress the brake to release the interlock in-order to shift into a drive or reverse gear. This system is powered by electricity. The fuse may be blown. Check the fuses for faults. The brake pedal / brake light circuit must be functioning in order to put the car in gear. Check the blue 10amp brake light fuse. Make sure the wiring in the trunk does not have breaks that may cause the fuse to blow

Here's another idea-Alot of different auto makers use a plastic piece inside the shifter housing that helps it shift into gears. From my experience with automatic transmissions this is a fairly common problem, though mostly with Dodge vehicles. Take the cover off of the shifter base and look for a little plastic piece on the bottom of the shifter. This piece gets broken alot, usually from time or heat, and once it breaks the car will not shift. You can manually move this piece to shift for a temporary solution, but it will need to be fixed. Unfortunately unless you can fix it yourself you are looking at about $200 from a dealership. Hope this helps!