The Presidential Preference ballot is April 4th, 2020.
This is a closed ballot, so only Registered Republicans can vote for the Republican candidates.
There are 5 Republican candidates on the ballot. See the Louisiana Secretary of State site for your sample ballot. Link
The five candidates are:
Donald J. Trump (the Incumbent)
Roque “Rocky” De La Fuente
“Bob” Ely
Matthew John Matern
Bill Weld
click on their name to go to their website.