An ICO project issues a token to raise capital, so the question is is the number of tokens limited? When and how to distribute tokens?
Number of tokens are mostly limited and distribution of tokens depends on the project. Most of the time they send them at the end of the ICO process and to your wallet address.
It depends on each project, some projects will limit the number of tokens from the beginning and others will be based on the project's investment amount. Distribution is also quite varied, often as soon as the ICO ends or immediately through smart contracts.