There are several ways to transport molecular hydrogen. It can be transported by tube trailers when it’s stored in cylinders, or through dedicated pipelines (potentially even in liquid form, but costs are very high at present).
As an alternative to molecular hydrogen transport, a more efficient option is distributed hydrogen production by electrolysis very close to where it is needed. It’s actually better to transport the energy obtained from a renewable source through the power grid, which would also provide energy for an electrolyzer to produce hydrogen in the location where it’s needed.