Before wearing the ehram
Making an intention (niyyah) is the condition for wearing the Ihram. Without intention if Labbaik is said, then the Ihram is not at all worn. It is not enough to only intend for Ihram, but one has to add some kind of Dhikr, according to the situation. (Al-Fatawa Al-Hindia, Chapter-3, volume-1, page 222).
Hence, after wearing ihram with the intention,  now you can recite labbaik or in its place recite,  for example  (اللہ اکبر ،الحمد للہ ،لاالہ الااللہ).
At the time of wearing Ihram, say Labbaik with the intention, since this has become well known many a time that intention (niyyah) is meant to be the inclination of the heart towards something. If there is no intention in the heart, then there would be no ihram, and it is better to say by the dialect, for example:
in the Qiraan method of Umrah say : (لَبَّیْکَ بِالْعُمْرَۃِوَالْحَجِّ)  and in the Tamaththa  method of  Umrah, say: (لَبَّیْکَ بِالْعُمْرَۃ), and in the
Ifraad method of  Umrah, say: (لَبَّیْکَ بِالْحَجِّ ).
(Ad-durrul Mukhtaar and  Raddul Muhtar, Book of Hajj,  Chapter of  Ihram, Volume-3, Page 560)