How to know date of incorporation of HUF

You can take the same from income tax department by giving PAN of the assessee. You can take the same from any ward or circle of Income Tax Department. You can ask to any of the clerical staff of your confidence they will provide you the same. 

only pan card or by seeing  date mentioning in previous return copies

the date of birth of first male child of karta is teated as the date of incorporation of HUF

Please tell me

Can we form HUF if child (male/female) is adopted ?

if yes

What will be parameter to determine the date of Incorporation?

Date of incorporation will be date of adoption.