Internet shutdowns are designed to block people from sharing information and communicating (and also push people into less secure forms of communication such as mobile phone and SMS, which are easier for authorities to intercept and monitor). There are not always good workarounds during complete shutdowns.
We don’t have sure-fire ways to circumvent all blockages, but through conversations with activists and peers, we have learned some methods and approaches for offline sharing and communication that may work for you, depending on the circumstances. Note that some of these options require internet to initially set up (e.g. to download apps, etc).