If you are sending people on a missions trip or to camp and want to allow people to donate to a general fund for the trip, you can set up a fund in Giving. Add a link to that fund in the description and confirmation emails for the Registrations signup, and adjust the scholarship fund balance as donations come in.
If someone wants to apply the donations to a specific person, the donation won't be tax-deductible and cannot be collected through the Giving Fund. The Admin or Manager would need to apply the payment directly to the attendee's registration.
From Giving, create a fund to contain all the donations for the missions trip.
In order for people to donate, put the fund's direct link in the event's description.
When someone clicks that link, they'll be taken to the giving page with the missions trip fund auto-filled.
Include the link in a custom confirmation email as well, to give people more opportunity to see it.
As donations come in, you can add them to the overall scholarship amount to be able to apply scholarships to attendees.
View the fund from Giving and create a scholarship with that amount in it.
As more donations come in, change the amount to the total reflected in the fund.