Hello everyone hope things are going well.
Im gonna be playing a shadow sorcerer in my next campaign and i wanted to add expanded spells to it (like both subclasses from tashas). So I was wondering whats de easier way to do it

If you're happy to use existing homebrew then I've created an unofficial shadow sorcerer variant with a spell list (currently unavailable); the sub-class does have some other changes, but nothing that massively alters how it plays. However for public homebrew there are limits on the spells I could pick, so you may or may not be happy with the list that I've chosen.

Otherwise the way to do it is to use the option to create a new homebrew sub-class, choose Sorcerer and then below that choose Shadow Magic to copy that sub-class. Once you've done that you'll want to add a new feature called Shadow Magic (or whatever you prefer), feel free to copy/paste the table from my homebrew for the description, and adjust the spell selection as you please.

Once you've saved the feature you should be able to see the Spells section for it, this is where you grant access to the actual spells themselves (the table is just to inform the player of what they get and when). For each spell you need to add one entry, set the correct spell, set Consumes Spell Slot to Yes, set Counts as Known Spell to No, set Always Prepared to Yes, and then set Available at Character Level to the correct character level (1 for a 1st-level spell, 3 for a 2nd-level, 5 for a 3rd-level, 7 for a 4th-level and 9 for a 5th-level). Repeat this for your entire added spell list, then give it a test on a character you're happy to level up and down (to make sure the spells come in at the correct level, and are castable at the levels you expect).

Hi I tried doing this with the Draconic Bloodline subclass but whenever I level up the higher level spells don't show up (no 2nd level spells at sorc 3, 3rd level spells at sorc 5, etc.) is this a bug or is there some configuration I missed?

Quote from vvsan1 >>

Hi I tried doing this with the Draconic Bloodline subclass but whenever I level up the higher level spells don't show up (no 2nd level spells at sorc 3, 3rd level spells at sorc 5, etc.) is this a bug or is there some configuration I missed?

That's hard to say without knowing more; the setting that determines when a spell entry will appear is the Available at Character Level option, which you should set to the class level which you want the spell to appear, so a 2nd-level spell on a Sorcerer should be set to 3, a 3rd-level spell set to 5 and so-on. Beside this option the only other fields you want to touch are Spell (set to the spell you want), Consumes Spell Slot (set to yes), Counts as Known Spell (set to no), and Always Prepared (set to yes); everything else should be left to the defaults.

You need a separate spell entry for each individual spell you want to add, so you should have 10 total if you're going for the usual pattern of 2 spells each of 1st- to 5th-level.