If it is about    (as your post says it),

then use the formula for the future value of a simple interest account 
    
    FV = P*(1+rt),


where P is the principal amount;  r is the annual percentage as a decimal; t is the time in years.


In your case,  the given values are

    FV = 7000  dollars;

    r = 4% = 0.04;

    t =  years.


     P is unknown principal (how much to invest).


So, your equation is

    7000 = P*(1 + 0.04*(22/12)}}} = 1.07333*P.


From this equation,

    P =  = 6521.60 dollars.


ANSWER.  You should invest  $6521.60: it is your principal.