Building a character in Shadowrun is a lot of fun. It's not quite the roller coaster that Traveler or Dead Earth are (for instance, you can't die during character creation in Shadowrun), but it's a detailed system in which you map out your character's life and education prior to running the shadows.
Shadowrun is a skill-based system, though, so unlike D&D it has no class system, no quick template to apply based on your character's anticipated role in the game. Every player character in Shadowrun starts out with nothing aside from maybe a few traits specific to their species (their "metatype"). It's up to you to configure their attributes, choose their skills and qualities to formulate their character. It can, to be honest, be a little overwhelming at first.
You can spend hours poring over the character build section of Shadowrun 5th Edition, and you might end up assembling something that makes sense, or you might end up with a smattering of skills and qualities that feel like they've been taken out of a lucky dip. There are lots of choices, and nobody wants to be a jack-of-all-trades. You want your RPG character to be very good at something.
I used to look online for pregenerated characters (pregen) so I could hand them out to my new players. I got mixed results with this tactic, though, and as it turns out the Shadowrun rulebook already provides pregens. I'd overlooked them for years, or more likely I saw them early on and then forgot they were there. The pregenerated characters in the rulebook are called archetypes, indicating that the builds followed several of the common build paths that have emerged over the years, such as tank, street samurai, street shaman, combat mage, face, decker, and so on.
The archetypes start on page 112. It's up to you to transcribe the stat block onto a character sheet (or you can just read off the stat block, I guess.)
The archetypes are useful in a pinch, especially provided that you already understand the Shadowrun system. For those unfamiliar with the system, I find pregenerated characters can be confusing because there's no context for what the values mean, or how good or bad they are. So when you use archetypes, be sure to read them over in advance, read up on the skills and spells, and be ready to explain the fine details to the player.
For that very reason, it's also best to start out simple. If you're bringing an archetype build for just one new player, offer just two choices: one fighter, one magician. This way, you only have to read and remember two builds. If you're bringing archetypes for the whole table, only offer one more build than required. The person last to choose still gets a choice of what to play, but a limited choice.
It's also important to understand that Shadowrun character building is something of a minigame. You choose really cool skills, you take both good and bad qualities, you choose a lifestyle, you buy gear, you establish contacts. By the end of it, you have a character with a background and history and a whole life aside from shadowrunning.
The disadvantage is that your gaming group doesn't get to the actual game until after, potentially, an entire session. That's one whole session of not playing a thing that's identifiable as a game. For experienced RPG players, that's probably not a big deal, but for new players it can create a confusing first impression. There's no right answer aside from communication. Tell your players that building a character can take a long time, but that it could be a fun and relaxing "soft opening" for your future game sessions. If you sense it might be better to just get started playing, then offer them archetypes to choose from. If they seem interested in the lore of Shadowrun and are eager to create characters of their own, schedule a build session.
Either way, there's a lot of potential wrapped up in a Shadowrun character, and it all starts with a build (regardless of who's doing the building.)