You can accept payments from anyone (in any country) with an accepted credit card or PayPal account.
Remember that there may be extra fees collected by Stripe and/or PayPal – and your supporters may face international payment charges – and you might be dinged by currency conversion.
There may also be restrictions in certain countries for their residents even to be allowed to contribute to a crowdfunding campaign.
Also, legal tax receipts can only be collected by those in the same country as the registered non-profit organization.
ConnectionPoint, however, has no restrictions on who can contribute to a campaign.