This is a question that took a long time for me to answer. Being very interested in angel investing early on, but lacking the proper capital, I was always wondering how to get into deals. Coming from Austria, a small country in Europe, I tried to invest locally first. I went the route of asking many angels here how to go about this, and the answer I got more often than not was: It doesn't make sense to write checks below 50k per investment. Those "small" checks could then be syndicated through contracts and shares be held by one investor as a trustee. I was quite disappointed but kept on looking for better ways to invest small checks as I believe investing a little in many startups will give better returns than going big with just a few, there is also data about that here. Enter SPV Providers.
Angellist.com allows investors to syndicate their investments in a Special purpose vehicle (SPV) while taking care of the administrative (boring) stuff. This was a few years ago, and no similar solutions existed for Europe. Until recently, the "cambrian explosion" of SPV providers happened. You can find more about all of them on this website (which I created) and compare them: https://spvproviders.com/
What I learned from this is the gist of this article: It is possible to use an SPV to wrap up many small investments with the help of any of those services.
Since then, I have recommended many founders to use such a service to be able to accept also smaller tickets for their fundraising. From a founder perspective, it makes total sense in my eyes to have many small checks onboard, as quite early on you can have dozens of people rooting for you and also help with marketing, sales, and connections.