Depends in what part of the titration you are.
At 0% of the titration the pH is calculated as the weak acid
You have to calculate how much acid and how much base has been add, and how much salt has been formed.
At 25% of titration the pH will be equal to the pka of the acid.
Between the 0% and the 100% you calculate as a buffer solution.
At the 100% everything is salt. you calculate has a salt of a weak acid and strong base.
After the equivalence point you calculate the excess of base concentration and you calculate the ph as a strong base. The contribution of the salt is not significant.
You can look for some vid from khan academy
