Validity & registration

dear ,

1.any agreement made in stamp paer or even in plain paper even if not notarised is a valid agreement .

2.there is no where mentioned about the compulsion of notarisation of all agreements but notarisation makes the authentification of a agreement easily proved in court if any dispute arises.

3.even if you notarised your agreement today the date of validation of agreement will remain the same as before.

Thank you for your kind reply.

Any agreement made in plain paper normally does not have any validity in the eyes of Court.

When we want to submit the agreement (not notarised but executed in stamp papers) to any government office like Sales Tax office, etc they do not accept as valid docs. They simply reject by saying invalid doc. How to justify on such situation?