My wife is doing a talk to a group of adults on how to get kids to actually give to charity (by choice). Surprisingly if you simply tell your kids, “You must give $10 to the Church“, they might cough up the money once, but will resent it and more likely never give much again (even as Adults).
Explaining to kids that they don’t just have to donate money, they can donate their time and talents, instead, is a first step. Getting kids to understand the importance of charity (and how they have so darn much anyhow) and helping those who need help is not easy and if anyone has any good stories about when they tweeked into the importance of Charity (and what age they were at the time).
Charity is a learned skill in many ways, teaching your children that Stewardship is an important aspect of giving. Give of your time, give of your skills, and give money when you can.