Technology is not just about machines, complex robotics or software as we know it today. In the Victorian era, even social change was classified as technological.
Production technologies serve to increase your economic efficiency in various ways. These are usually very concrete inventions, like cotton gin, which increases the production of cotton plantations, and dynamite, which can be used in all types of mines for higher yields.
Sometimes they are more abstract, such as B. Fencing, which is a requirement for building modern privately owned farms and ranches, or shift work, which is more effective at using the workforce in your manufacturing industry. Production technologies also include advances in railways, and some even unlock unfamiliar goods like rubber, electricity, and cars at the start of the game.
Military technologies improve your army and navy. These consist of a mix of new weapon technologies, doctrines, and ways to organize your soldiers and officers. With rifles, you can switch the production methods in your arms industry from muskets to rifles, thereby increasing the production of small arms.
Social technologies are all about new ideas for organizing society. This includes ideas related to politics, finance, and diplomacy, to name a few. Democracy allows various electoral laws and republican governance principles to be passed. Pan-nationalism is a prerequisite for the formation of certain larger countries and leads to political agitation that both makes your people more politically active and, for example, gives you more authority to deal with them.