I wanted to ask that is it good to giving 12v to 12v operated relay from 230v to 12v transformer+ rectifier + 1000uf 50 v capacitor , I am taking 12 v and ground from capacitors legs !
Under normal conditions you can do exactly that if the relay has a coil rated 12V DC. You may not even need the capacitor but it could reduce humm and/or buzzing in some cases.
If the relay coil is 12V AC then you can leave out the rectifier and capacitor and drive it directly.
The two types of relay have some minor differences so it is best to follow the manufacturers ratings. Some relays are rated for either AC or DC. Typically a DC rated relay will not pick up with the same AC voltage while a AC rated relay may hold the contacts closed for a bit longer or sometimes until it is bumped as the armature may have become excessively magnetised.
Transformers usually supply a bit more than the rated voltage when not loaded but under some load they should droop to close to the rated voltage and this should match what your relay needs.
Your relay's datasheet, model number or supplier link would help confirm your use case.