In this documentation, we can check how to change default welcome message in Magento.
1) Login to Magento admin panel.
2) Go to ‘System’.
3) Click the option ‘Configuration’.
4) Go to General >> Design.
5) Select the option ‘Header’.
6) Type the new message in the textbox ‘Welcome Text’.
7) Click the button ‘Save Config’.
That is how we can change default welcome message in Magento.
If you need any further help please reach our support department.