Hello @Kar17 and welcome to the SAS Support Communities!
This appears to be a kind of standard footnote used in SAS Enterprise Guide. Posts by different users contain the identical FOOTNOTE statement creating it:
FOOTNOTE1 "Generated by the SAS System (&_SASSERVERNAME, &SYSSCPL) on %TRIM(%QSYSFUNC(DATE(), NLDATE20.)) at %TRIM(%SYSFUNC(TIME(), TIMEAMPM12.))";
(found, e.g., here and here).
So, submit the above statement before your PROC TTEST step and the desired footnote will appear as shown in your screenshot. (Assuming that your are using SAS Enterprise Guide, as otherwise macro variable _SASSERVERNAME might not exist.)