Ukraines army was woefully unprepared for the Russian invasion due to years of neglect and corruption under the previous government. As a result Ukraine needs a lot of help to rebuild their armed forces and defend themselves against Russian aggression, here are a number of verified ways to donate:
Many of those sites, like this one and this one, allow you to choose which project you would like to donate to (like medicine, humanitarian aid, UAV's, bullet proof vests, etc).
Join the Ukraine information army
Fight the propaganda and lies of Kremlin paid trolls all over the web with objective truth, link to facts and expose lies & misrepresentations. Join Ukraine’s information army, they send out regular newsletters with links where trolls are likely to spread their disinformation so that people who believe in doing what is right will hopefully combat it by presenting the objective & verifiable truth.