If you are just using online tool and your goal is absolute PPP position with millimeter accuracy, you`re in for a minefield of traps. Its recommende to use a local dedicated transformation tool for you area. The european tool i linked to might not be the right one for you, its designed to do translation on the Eurasian Plate.
E.g for my area in Norway, this means 5 steps to get me in the 2-4cm ballpark with PPP.
With a 2hour observation processed at NrCan, the XYZ ITRF2014 before WGS84 translation is used.
Next is 5 step translation:
-ITRF2014-ITRF2000 no velocities
-ITRF2000-ETRF2000 no velocities
-ETRF2000 (used epoch) - ETRF2000 (Epoch 2000 which coincide with common refrence frame at epoch 2000) velocities used
-ETRF2000 (epoch 2000)- ETRF93 (Epoch 2000) no velocities
and final step
-ETRF93(epoch 2000) - ETRF93 (epoch used for PPP) velocities used
Final steps is concide with our national refrence frame EUREF89 at millimeter level
Importat thing during these steps is to use a proper 𝑇𝑋/𝑇𝑌/𝑇Z speed model and intraplate deformation values.
With this generic model i used, it will only get me in the ballpark , hence 2-4cm of target.