Hi. You need to specify what you are trying to convert. If it's hair or accessories, google " the sims 4 convert hair fro, adult to child", you will find videos and written tutorials. If it's clothing, then it's more complicated
PLEASE FOLLOW THE RULES OF CREATOR HELP:
describe your problem and provide a picture of it (if possible);
provide download link(s) to .package and .blend files.
If you have a Gmail acc, you can host all of the above on Google Drive
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