美国办去加拿大签证吗？
首先，没有所谓美签加签的区分——所有非美加公民想要进入美加两国的签证都是visa(签证) - Nationality is irrelevant to whether you need a visa or not. If your nationality requires that they issue you with a visa before allowing entry into the country， then you will get one (and there are many countries for which this applies)， just like anyone else would.
Secondly， Canada has no "visas on arrival" scheme as far as I know（虽然我不是很确定）； visas are always issued prior to travel， and it's really just an electronic document in most cases; at border control both Canadian citizens and permanent residents have their passports stamped by the immigration officer if they arrive from outside of North America， but non Canadians don't even have to show them to gain admission - all they need do is present proof of citizenship/residency along with valid passport-free documentation such as a NEXUS card. As long as these other documents are in order then any non Canadian can be admitted without issue provided they were issued from an approved country， so basically anything in the Americas except Mexico & Central American countries. This includes all EU countries.
As mentioned above， US citizens travelling between each other never require either a visa or an ESTA authorization when crossing into each other's territory under regular conditions. The only people who ever use those things are foreigners wishing to enter either country. However， some Americans might find themselves temporarily denied reentry based upon what they've done overseas during their trip， especially if it was deemed suspicious activity by Homeland Security agents investigating it further back home. For example having stayed too long somewhere might cause problems later down the road depending where exactly within that destination's borders someone chose to stay， because while technically speaking traveling between two cities within China doesn't count towards overstaying an authorized period abroad anywhere near enough to warrant investigation here it still does mean that Chinese authorities could