volunteer hours

Try checking your school district's website or ask your guidance counselor. Most likely, you can have your volunteer hours added by filling out a specific form that has to be signed by someone from the place you volunteered at, like the director or supervisor of some sort, who verify you actually participated and for what hours, then it has to be approved and added to your transcript by your guidance counselor. My district has a rule that volunteer hours to be counted on your transcript have to be from an activity that was pre-approved by the guidance counselor before you did it. If yours has a similar rule than the hours you have already might not be able to count for your transcript.

check if your school has a form where you fill out your volunteer hours, which usually has to be signed, if it's nowhere to sign, talk to someone in the office, or your guidance counselor.