There are two options for creating more secure bike parking for yourself, but you’ll have to assess which one is the best option for you based on the context.
Get a good lock. If you work somewhere with lots of signs, bike racks, or other objects you can lock to then you’re probably safe buying a u-lock (or two), or a heavier but very serious chain lock from someone like Kryptonite. We've got a guide to finding the right bike lock here.
Request secure bike parking. You’d be surprised how many offices install bike parking once someone asks for it - in many cases they’ve just never thought about it before, and it turns out there’s a giant broom closet downstairs that could become a bike storage room overnight if you ask! Sure, that doesn’t always happen, but if you don’t suggest it it definitely won’t.
Now sometimes neither of those are options, and neither is bringing your bike into the office. If that happens, reach out to a local advocacy organization in your area and let them know your plight. They may know who to talk to, or be able to pass along that need to a local partner.