I cannot graduate from high school because the school is closed. Can I still start college or university? I was recently accepted by a college or university.  I was planning on graduating from high school soon and then enrolling in college.  My high school has just announced that it will be closed for a reason such as the COVID-19/coronavirus pandemic.  Will I still be able to start college?

(Question limited to students who are already admitted.)
Ask them.
You mentioned that they accepted you already. Only they can tell you whether the admission process is affected by the recent events and whether they're willing to accomodate last minute changes to your academic schedule.