Open phpMyAdmin and select the database from where you want to export data and/or structure. Go to the tab with "Export". Select the table(s) you want to save. Select the option you need: Data only or data and structure or structure only:

--> if you only want to update a table on another server, which has a table with the same structure, then you choose data only 

--> if you want to create a new table on another server (for instance, if you have a development environment and you now want to put your application in production) then choose structure only 

--> if you are moving a complete table, choose data and structure

Select "save as file"

Hit "go"

You can now enter a filename and specify where the file needs to be saved. It's recommended to choose a meaningful filename that includes the date. Like "user_06_05_04.sql"