You can add an explanatory note after you add in the donation and before you confirm to send the donation.
"He who sows sparingly will also reap sparingly, and he who sows bountifully will also reap bountifully. So let each one give as he purposes in his heart, not grudgingly or of necessity; for God loves a cheerful giver." (2 Cor 9:6-7)
Parishioners at St Nicholas are encouraged to be good stewards of the time, talent, and treasure God has bestowed on them. This stewardship involves acknowledging that "every good gift and every perfect gift is from above, and comes down from the Father of lights," (James 1:17) and then taking a first portion of those gifts to offer them back to God in thanksgiving. In November of each year, parishioners are encouraged to plan out their offerings for the following year so that the parish can continue the work in the community which God has planted in our midst.