Which master degree will be best in UK; one or two year for PR in the country?

Well, there is a very simple answer to your question. It’s definitely one year master's in the UK. One-year and two-year masters are not much different, to be frank. It’s just that a one-year master's starts directly with your specialization. This makes it faster to get graduation and start working in the industry. So I guess it's pretty natural that a one-year master's is better. Why getting a job early is important you ask?

Permanent residency is not granted anywhere with just some documents. To get UK PR, you have to get a full-time job there. After some time passes (5 years to be precise in the UK case), you can apply for the ‘indefinite leave to remain’ ILR Visa. This visa grants a person permanent residency status in the UK. But as you can assume, there will also be attesting to get this done. Knowledge of Life is the UK test that you have to clear.

Also, you will need to get an English language proficiency test done. I know you would have already attempted IELTS or TOEFL for your masters, but the score validity for these tests are 2-years. Therefore you have to attempt the test again. However as you have already done it and passed the exam, it should not be a task for you.

Not to mention, UK universities specialize in one-year master's. All your prospects and logic point towards a one-year master's degree. I can explain more if you wish to know. Feel free to contact me for any information regarding this topic.