Many US employers who hire remote workers in Canada often wonder if they need to get US-issued H-1B or TN-1 work visas for them.
The simple answer is no, because these workers are not working on American soil and therefore the US government does not require work visas for your company to hire them to work in Canada. However, if these workers need to travel into the US to work on American soil (e.g., if they need to service your domestic US clients or do actual work at your company facilities), then your company does need to get a work visa for them, even if they work mostly in Canada.
On the other hand, if your remote Canadian worker only needs to enter the US for business meetings, such as receiving instructional directions or training at your office, then a work visa is not required. This is because Canadian citizens are already allowed into the US for business meetings, trade conferences, and attending training seminars with their passports. Canadian permanent residents (PR), are afforded the same treatment if they obtain a US issued B1/B2 business and pleasure visa. This is a multiple entry, 10-year visa that is fairly easy to get.
A typical business trip for a meeting or conference lasts one week or less. US border agents may start questioning your remote worker if they consistently need to be in the US for several weeks or months at a time.
Because your company is now the client of the Canadian-based PEO agency, your remote worker must identify the PEO agency as their employer, not your company. If the remote worker says they are employed by your company, it is expected that they will have a US work visa. Canadian workers working for Canadian employers can also enter the US to meet with American clients. This is effectively what is happening when your company sub-contracts our PEO agency to be the employer of record of your remote worker.