Sec 44AD to partner of a firm

He can't declare the salary or interest received from firm under 44AD. However if he has any business other than that of firm, he can opt 44AD for that business.

Presumptive taxation can be opt by an assesse who is carrying on bis own business or profession.

As per sec 28, interest/remuneration from firm is chargeable as business income in hands of partner.

Yes. But the partners collectively carrying on the business right? It is not only by the Indivdual partner.

Any income received from the firm by the partner is chageable to tax under business income u/s 28 and he need to file ITR 3 and not ITR 4 which is presumptive taxation.

So the partner cannot opt presumptive taxation any way.

Can he claim expenses against this income. Eg. Salary to his driver, assistant etc., Depreciation on his vehicle, Travelling expenses etc...?

Partners business expenses can be allowed u/s 37(1) if he can prove the nexus of such expenditure to earn income from the firm.

In case the expenses found to be personal in nature the same can never be allowed.