Make sure you have an IP assignment with everyone who’s worked on your product or idea without a formal contract in place - this ensures your company owns their contribution, and not them.
When you first start building your business, there’s often a lot of people working on your product and other intellectual property. These might be potential co-founders or team members, advisors or even contractors that you hire (for example contractors for your website).
The IP that they create, even if it’s clearly for your business, doesn’t necessarily belong to you unless you have an IP assignment in place. There are many examples of founders not having their IP protected, causing an expensive dispute which can make you all but uninvestable.
An IP assignment ensures that any work they do for the benefit of your company, even if it was before your company was officially incorporated, belongs to your company. There is sometimes payment as part of this, which normally is either a nominal figure or what was initially agreed e.g. the contractor price for your website.
Ideally, you should make sure you have an IP assignment in place with everyone who has worked on your product, even if you don’t consider their contribution to be material to avoid any potential disputes in the future.