Peace be upon you and God's mercy and blessings.
Grand Ayatollah Sayyid Khamenei and Grand Ayatollah Sayyid Sistani (may God protect them):
Lying is prohibited; it is the act of intentionally reporting something contrary to reality. A liar knowingly conveys information that is false.
However, it is permissible to use ambiguity, which means to convey a meaning that is true but not the apparent one.
Lying is allowed in the following cases:
First - to prevent harm to oneself.
Second - to prevent harm to a believer.
Third - to reconcile between believers.
Grand Ayatollah Sayyid Sistani:
It is strongly recommended to limit the cases in which lying is permissible to situations where ambiguity is not feasible.
Source:
Grand Ayatollah Sayyid Khamenei (may God protect him): Special Inquiry: 1, 2.
Grand Ayatollah Sayyid Sistani (may God protect him): Al-Minhaj Al-Salihin, Vol. 2, Issue 38.
May you be successful in all good.