Decide how you want to help needy students. You can purchase the required items personally and give the school supplies to either the management of any particular charitable organisation or can give it to the students yourself.
In order to provide help to deserving students, you first need to figure out where they are. For example, you should visit different schools in various areas to make sure the students have all they need tools to study. You can find organisations on the internet that provide data on those who need financial assistance.
If you are wealthy enough to contribute money, then donate it to students who are lacking school supplies. You can help them buying neat school uniforms, writing materials and various course books etc. You can transfer the money to any foundation and ask for the financial reports indicating where the funds were spent.
If you are not capable enough to help students yourself, you can generate income for them after asking wealthy individuals to make donations. However, you should show your complete plan on how you will provide the supplies to the students.
Ask people to give old uniforms that their children no longer use. You can collect all of these from around the community and donate them to needy students. There are other school supplies that you can acquire from others through donations.
If you are personally know any low-income family, visit them and tell them that you will assist them in buying school supplies for their children.
You can also register a charitable organisation for this purpose. First define the objectives that motivated you to start the organisation and develop your charter. Once complete, you can now legally ask for donations and help others get school supplies.