The nonprofit-centric website builders on this list have inbuilt tools you can use to accept donations on your website.  The rest of the general-purpose non-profit website builders with custom domain features (aside from free domain) allow you to integrate third-party tools, such as a GoFundMe campaign page, PayPal request page, or other external donation pages to accept online donations easily.  But of course, unlike other website builders, if you are already building a website for your nonprofit organization, it may be better to accept donations on-site rather than sending donors to external pages, which would likely drop your conversion rates.