I work as a software/firmware engineer for one of the largest companies that designs the products that most companies use for employees working from home. We are US-based but have offices worldwide, including in China. Most of our customers have either transitioned to home work or are actively testing it. (been great for our stock price so far).
(I also do some side work as a hardware/firmware engineer for a small embedded design company; I work 2000+ miles away from them and have never actually met any of them, so it's business as usual for me regarding that stuff)
I think it won't be a big deal for many companies, because a lot of at least the larger companies already do a lot of work from home anyways. But capacity planning, etc are important. If anything goes wrong, it will be with underestimating the resources required, licenses, etc.
As for us, we did a worldwide test on Thursday, of our tech support teams, just to load test our existing systems. Most of us work from home a few days a week, but never all at once, so we wanted to ensure there were no surprises. Went pretty smoothly and it was now announced that starting Monday, working from home is "highly encouraged" for all staff, worldwide, except the few who have to be "hands on" in the office. We are not closing offices (you still can come in if need be) but most people won't. For us, being most of the company at least occasionally works from home anyways, I doubt it will affect our operations much. (I WFH about 3 days a week usually). Our China and a few other overseas offices were already on mandatory work from home with the offices actually closed and they are starting to transition back into the office, now.
Incidentally, our sales and consulting teams were told not to go INSIDE any customer's office without approval. Also both foreign and domestic travel now require approval, as well.