Data Management - Tagged Questions

• How to check duplicate entry in excel?
• In Microsoft Excel I want to combine the contents of two cells like first name and last name into one cell. What function should I use—CONCATENATE the "&" operator or the newer TEXTJOIN?
• My phone's SD card is full and I'm getting storage warnings. What's the safest procedure to free up space—should I delete files directly format the card or transfer data to a computer first?