You have to find a genuine employer who will offer you a job and that employer would apply for an LMIA. You obviously dont find an LMIA without an employer and generally it is impossible to secure a job from outside of Canada as employers are not keen to sponsor LMIAs unless osmone has unique skills not readily available in Canada.
Also note that given COVID the unemployment rate is likely to increase significantly so LMIAs are likely to become even harder to come by for the forseeable future as there will be a surplus of residents looking for work.