cant put it in drive

Not enough info. Stick? Check clutch flud, slave and master cylinders. Auto? May be simply detritus falling into shift interlock pin area; to check, remove plastic console cover and clean up area under there. Pin should "click" into and out of lock when brake is applied and lever button depressed...thus allowing pull-back through N to D. French fries, milk, coke syrup, raisins...I've found it all in there over the years!