Games Workshop knows that painting all those insignia and numbers can get tedious, so they’ve made new waterslide transfer sheets that they’re now taking pre-orders for.
From the update:
Available for you to advance order today are 10 sets of transfer sheets specific to particular Space Marine Chapters. From codex to non-codex Chapters, each transfer sheet is full of heraldic devices, including Chapter symbols, squad markings, and campaign markings. Quick and easy to apply, these transfers give you a consistent finish for your army. So whether you’re starting out with a squad of Salamanders or have just added a Rhino to Harald Deathwolf’s Great Company, there’s now a wide selection of iconography to help give your army a professional finish.