Some charities have their own fundraising pages which you can use to donate all the money you have raised during a charity event or you can create your own, free fundraising page on popular sites like JustGiving or Virgin Money Giving. This is a really easy way to fundraise as the money will be sent directly to your charity, but please be aware, normally a small percentage of the funds will be taken by the site to process the donations.
Share a link to your fundraising page on social media to encourage people to get involved and support you.