How to pass variable to another Keywords

Variable ${arg1} is null in keywords Open the intranet website ${path_file_pdf}

How can I set the value of a variable ${arg1} to the next one Keywords?

*** Variables ***
${path_file_pdf} “”

** Tasks **
Finding files recursively
Open the intranet website ${path_file_pdf}
Convert file PDF to Excel

** Keywords **
Finding files recursively
${files}= Find files %{ATTACHMENT}/*.pdf
FOR ${file} IN @{files}
${path_file_pdf}= Set Variable ${file}
Absolute Path ${file}
END

Open the intranet website
Open Available Browser ${urlsite_convert}

Convert file PDF to Excel
# [Arguments] ${arg1}
Log %{PATH_FILE_PDF_CONVERT}
Log ${path_file_pdf}
${nmfile_pdf}= Get File Name ${path_file_pdf}

Click Element    id:chooseFileBtnTrue
# This can be any one file
# Add file input    name=file    multiple=True    source=${attachments}

Log    Selected file: ${path_file_pdf}

Log file:
KEYWORD Finding files recursively

Start / End / Elapsed: 20221202 19:52:18.223 / 20221202 19:52:18.234 / 00:00:00.011

00:00:00.001KEYWORD BuiltIn . Log %{ATTACHMENT}

00:00:00.000KEYWORD BuiltIn . Log %{FILENAME_PDF}

00:00:00.003KEYWORD ${files} = RPA.FileSystem . Find Files %{ATTACHMENT}/*.pdf

00:00:00.006FOR ${file} IN [ @{files} ]

Start / End / Elapsed: 20221202 19:52:18.228 / 20221202 19:52:18.234 / 00:00:00.006

00:00:00.005ITERATION ${file} = C:\Users\marmi\OneDrive\Documentos\RPA\Robocorp\pesquisaPostagens_04-11-2022.pdf

Start / End / Elapsed: 20221202 19:52:18.229 / 20221202 19:52:18.234 / 00:00:00.005

00:00:00.001KEYWORD ${path_file_pdf} = BuiltIn . Set Variable ${file}

Documentation: Returns the given values which can then be assigned to a variables.
Start / End / Elapsed: 20221202 19:52:18.230 / 20221202 19:52:18.231 / 00:00:00.001

19:52:18.231 INFO ${path_file_pdf} = C:\Users\marmi\OneDrive\Documentos\RPA\Robocorp\pesquisaPostagens_04-11-2022.pdf

KEYWORD Open the intranet website ${path_file_pdf}

Start / End / Elapsed: 20221202 19:52:18.234 / 20221202 19:52:29.725 / 00:00:11.491

00:00:00.000KEYWORD BuiltIn . Log ${arq1}

Documentation: Logs the given message with the given level.
Start / End / Elapsed: 20221202 19:52:18.235 / 20221202 19:52:18.235 / 00:00:00.000

19:52:18.235 INFO “”

Where is your varibale defined? In general you can pass variables from keywords by using Arguments and RETURN. Or set variable as global and setting value from keyword.
https://robotframework.org/robotframework/latest/RobotFrameworkUserGuide.html#variable-scopes