Libertarianism and fascism are so far apart that I'm not sure if this question is just trolling, but I'll give it the benefit of the doubt.
Libertarianism generally supports the idea of minimal government intervention in people's lives. This means both avoiding restrictions on what people are allowed to do (e.g. legalize drugs, oppose religiously-driven laws that restrict the freedom of gay and trans people), and also avoiding governmental efforts to actively assist people (e.g. no social security or Medicare). Most libertarians would like to see a small, weak government that just does the minimum required to ensure that one person's freedom isn't impinging on another person's freedom. They typically oppose military intervention - many oppose the idea of a standing military at all - and generally advocate for open boarders.
Fascism on the other hand generally advocates for a very strong government that aggressiveky restricts individual freedom in the hope of achieving the goal of social and cultural stasis, or national military power. Fascists typically believe that individuals should submit to the will of the state (e.g. dramatically limiting free speech, banning "deviant" lifestyles). They tend to support aggressive military actions and closed borders.
Libertarians believe personal freedom is an end in itself. Fascists seek security and safety for their immediate society and tend to not care much about personal freedom. Whereas libertarians tend to value every individual, fascists would argue that any given set of individuals should be sacrificed if it benefits the state.
As with any political identity though, there are a wide range of beliefs - and people - who have been identified with these two labels. So, YMMV.
