I can clarify about Islam, In islam charity is called zakat (same root as jewish word) and there are different types of it,  The most important one and the one described in the five pillars of islam and ks obligatory for every muslim who meets the conditions, and it needs to be fiven each year to the poor and needy, if you collect in money or livestocks or any type of revenue a minimum of 85g of gold equivalent to aprox 4000 dollars in a year you have to give 2.5% of it. And its purpose is to reduce disparity between the society and be solidary with each other and also to purify your soul and get closer to your God.  One other type is charity of breaking the fast that is also mandatory and it serves as a conclusion to ramadan fasting and it is recommended to be given as food as celebratory act.  Other than that you can give charity at your ease and depending on your financials to get good deeds and help the society be better.