You may wish to replace the default My Account Navigation Link icons with icons which are more appropriate and inline with your business branding. In our example, we have replaced the dashboard icon ( ) with a lightbulb icon ( ). To replace the icons, follow the steps in this quick guide.
Get the Unicode for the Icon you want
Head to Font Awesome and grab the unicode for the icon

Choose the Link You Wish To Change
Here is a list of the default my account navigational link li class names. Pick one to target
woocommerce-MyAccount-navigation-link woocommerce-MyAccount-navigation-link--dashboard // Dashboard
woocommerce-MyAccount-navigation-link woocommerce-MyAccount-navigation-link--orders // Orders
woocommerce-MyAccount-navigation-link woocommerce-MyAccount-navigation-link--downloads // Downloads
woocommerce-MyAccount-navigation-link woocommerce-MyAccount-navigation-link--edit-address // Addresses
woocommerce-MyAccount-navigation-link woocommerce-MyAccount-navigation-link--edit-account // Account Details
woocommerce-MyAccount-navigation-link woocommerce-MyAccount-navigation-link--customer-logout // Logout
Add this CSS to your my account page
body.woocommerce-account ul li.woocommerce-MyAccount-navigation-link--dashboard /* <- This is the Dashboard link */ a:before{
content: "\f0eb" /* <- This is the lightbulb icon. Include the backslash prefix */
}