What’s the difference between Infaq, Sadaqah, Zakah?

Question: What is the difference between infaq and sedekah and zakat. i want to contribute a part of my money i have received from my majlis kahwin for the needy to a mosque. do i say i want to infaq $xx amt of money? I am currently guiding a friend to pray. but she will take time to hafal the tahiyyat awal & akhir, can she just lafaz the syahadah for both sitting? – Anonymous, Singapore

Wallahu a’lam
Contributor: Ustaz Anwar Hussain