Documents required for Long term family visit visa

[Son_of_Soil]

Hi
I seek some urgent advise here
i am planning to apply for a 2 year long term family visit visa for parents in india.as per the requirement we must subit all document in originals.As i am in the UK ( on Indefinate leave to remain) ,i cnt send my original passport to india for them to apply.
can someone who has applied for this type of visa provide some guidance. They will not accept scanned/photocopies.

also, if you can provide me with a list of documents required please.
regards

[Wanderer]

Have they visited UK before?