By general rule.
You should have science related subject specifically biology at school level
Second , you will need MBBS( Bachelor of Medicine and Bachelor of Surgery) which is 4-6 degree (includes 1 year supervised training )
Third , you will need MD( Medical doctor ) with specialisation in psychiatry which takes 4-5 years .
And you are good to go to practice as psychiatrist!!
You may also want to check about "how to be neurologist" as there is quite overlap of work with psychiatry in practice
Note: years of training and licensing varies from place to place