Create a Custom Object from a Spreadsheet in Lightning Experience

If you prefer not to create a custom object and its fields manually, you can use a spreadsheet to add the object and its fields and populate all its record data.

Visual: https://www.youtube.com/watch?v=wA1SUuhLbiw

Reference:

https://help.salesforce.com/s/articleView?id=sf.dev_objectcreate_task_lex_from_spreadsheet.htm&type=5

https://trailhead.salesforce.com/en/content/learn/projects/quick-start-customize-an-app-with-lightning-object-creator/import-data-to-create-a-custom-object