You can donate money right from The International Red Cross – Ukraine Relief Efforts website. https://www.icrc.org/en/donate/ukraine
Sadly, there are a lot of scam sites that are collecting money using the Ukraine crisis to lure people. Doing a little fact-checking, this is what I found about the ICRC. The International Committee of the Red Cross (ICRC) is an impartial, neutral and independent organization whose exclusively humanitarian mission is to protect the lives and dignity of victims of armed conflict and other situations of violence and to provide them with assistance.
The Red Cross’ overall ranking on Charity Navigator is three out of four stars and an overall score of 89 out of 100. Founded in 1919, the International Federation (IFRC) is the coalition of individual Red Cross and Red Crescent national societies that coordinates peacetime humanitarian relief efforts throughout the world.