That's a great question. Ultimately, it will depend on what type of work is being done. The vernacular can be confusing, but typically, the term "mechanics lien" relates to lien claims in the construction industry that help to obtain payment for work performed. So, if you're in the construction industry, there are certain requirements surrounding the ability to pursue a mechanics lien to secure payment owed for work performed. If this is the type of lien you're looking for information on, we've got some great resources on the topic - like this Missouri mechanics lien overview, and this step by step guide on how to file a Missouri mechanics lien.
However, for mechanics doing traditional "mechanic" type work - like on a car, machinery, or watercraft - the process for obtaining a lien for that work is a little bit different, and it's a little outside our area of expertise. Though, there are some other resources available online that might be helpful. This guide, Creation and Release of Liens, looks like it contains helpful information, though it's from 2012 so it may be outdated. Further, Avvo.com and JustAnswer.com have sites where individuals can ask legal questions and receive answers on all sorts of topics, beyond construction payment and construction law.
Hope this was helpful! If you've got other questions about Missouri mechanics liens in the construction industry, or other questions on construction payment or construction law, feel free to come back and post another question!