This is awfull!

[AstroSpace]

Where is custom solar system button in most recent sfs update. And yes, I do have all expasions. Also, no files appear in "android>>data" anymore, that used to be the way to planet editing!

 

[New Horizons]

Step 1:
Download a planet Pack
Step 2:
Go to Files>Downloads and you will find planetPack.zip
Step 3:
Unzip
Step 4:
Move folder to SpaceFlight Simulator > Custom Worlds
Step 5:
Relaunch SFS

Hope This helps!
EDIT: this is my method of downloading solar system packs on my iPhone 7

 

[AstroSpace]

Well, thanks, but the problem is, there isnt any Spaceflight Simulator folder.

 

[New Horizons]

look at every folder you have