In addition to reporting your accident to local authorities, you should report it to your insurer. The precise length of time you have to do so will vary from insurer to insurer and policy to policy.
However, you should make sure to report your accident as soon as possible.
Many insurers will require you to report your accident soon after it happens, frequently within 30 days.
But after you report your accident, you may also need to file a claim, which is another thing entirely. Make sure to do this as soon as possible too.
Some policies may set specific timeframes in which you must file a claim. Other policies may not set a timeframe at all.
Thus, make sure to review your insurance policy to ensure that you follow the applicable timelines and requirements.