On the application, the insurer asks if you already own life insurance, and if so, how many policies and how much coverage you own.
There's no limit to the number of life insurance policies you can have, as long as an insurance company is willing to sell it to you.
However, it's much more expensive to buy four $25,000 life insurance policies, than one $100,000 policy, and you can split the money out any way you want. That's because there are fees associated with issuing a new life insurance policy, so, if you only buy one policy, you only pay the fee one time.
In addition, you may be able to add more coverage to an existing life insurance policy without having to take a physical exam, depending on your insurer and the amount of additional life insurance you need.
Here's an article that reviews the question - How many life insurance policies can you have?