My sable when l shift it into park it wont stay so lately l been having to put the Ebrake on so it stays in place. well l just recently notice thatwhen l do that it make like a sqeaaking noise on the rear end on the car like when l lean on it or get out of the car that is a sign of what!?!?

Movement in the wheel or cable..

Well several possibilities u could have a broken rear spring & when u apply the ebrake the cars suspension moves since it is whats holding the car from moving .
Or the rear brake shoes r squeaking against the brake backing plates when u apply the brakes the shoes expand & if there is no lube on the contact area of the shoes & backing plate they squeak. Or stabilizer links broken
As for ur shifting into park u may have a broken shifter cable or lose bushings at connections of the cable

Your emergency brake cable may have slack in it. Your rear brakes may need adjusting, or the rear brakes may be worn enough to where the brakes will not hold the car. The squeaking is probably the brake shoe rubbing against the drum, because the car is moving with the e-brake applied, because of one of the reasons l mentioned above. Have it checked at a repair shop.

if ur shifting lever is too loose ,,then ur shifting bushing is worn out,,but have somebody check the lower end of the shifter,under the dash & inspect the two screw that is holding the lever that is attach to a cable,because if the bushing is worn out ,you could still shift it in park, ,,

if every thing is secure in ur lever then u have a problem on the trans,your parking pawl is broken,,

is the noise the same when u apply the foot brake.if not
then just try to lubricate any moving parts under the car where u hear the noise,,,

Either your shift linkage has become out of adjustment between the gear selector and the transmission, or your ''Parking Pawl'' is broken.
The squeaking noise is just the rear brakes giving off noise because they are fully applied.