It used to be that launching TextEdit in macOS would open a blank document for immediate typing/pasting. At some point over the last several years, it changed to show the file picker by default.
To switch to the older functionality, run the following terminal command:
defaults write com.apple.TextEdit NSShowAppCentricOpenPanelInsteadOfUntitledFile -bool false
Switch false
to true
to revert the change.