There are 7 higher Lokas and 7 lower Lokas. I want to know about what scriptures describe each Loka and how it is decided which person goes to which Loka after death.
I cant give more information about scriptures describe each Loka. But hope his might help you a little bit.
There 7 higher lokas as mentioned
भूलोक, भुवलोक, स्वर्गलोक, महालोक, जनलोक, तापलोक, सत्यलोक
and 7 patals as mentioned
अतल, वितल, नितल, गभस्तिमान, महातल, सुतल, पाताल
If you read Gyatri Mantra then you will notice 3 higher lok mention in it
ॐ भू र्भुवः स्वः । तत्स॑वि॒तुर्वरेण्यं॒
भर्गो॑ दे॒वस्य॑ धीमहि । धियो॒ यो नः॑ प्रचो॒दया॑त् ॥
भू meaning भूलोक, र्भुवः meaning भुवलोक and स्वः meaning स्वर्गलोक.
And about how it is decided which person goes to which Loka after death is totally depended on the karma done by a individual person.
You reap what you sow.
I hope this might help a little bit.