Ya he terminado mi informe.

Yes. It’s grammatical everywhere. In much of Spain it can sound either more “past” or more colloquial/regional for something finished today. In Latin America it’s the default way to say “I finished my report.” Compare:

• Hoy he terminado mi informe. (Spain, common)
• Ayer terminé mi informe. (everywhere)
• Ya terminé mi informe. (everywhere; in Spain, often feels a bit more detached from “now”)

Here ya means “already.” Typical placement is before the verb phrase: Ya he terminado… You can also place it after the participle: He terminado ya, which sounds a bit more conversational or emphatic. Avoid He ya terminado, which is not natural. Other meanings to know:

• ya no = “no longer” (e.g., Ya no trabajo allí.)
• For “not yet,” use todavía no or aún no, not ya no.

With the auxiliary haber (present perfect), the past participle never changes for gender or number. It’s invariable: He terminado la tarea, He terminado los informes, He terminado mi informe. Agreement happens when the participle is used as an adjective (often with estar):

• La tarea está terminada.
• Los informes están terminados.

Not idiomatically. Estoy terminado can sound like “I’m finished/ruined” or overly literal. To say “I’m done,” use:

• (Ya) he terminado.
• Ya está. (colloquial: “Done/That’s it.”) For objects, El informe ya está terminado is fine (it’s describing the report’s state).

Both are possible:

• He terminado el informe is very idiomatic when the report is already identifiable in context (the one your boss/class asked for).
• He terminado mi informe emphasizes that it’s yours (e.g., contrasting with someone else’s). Note: mi trabajo can also mean “my job,” so for a school assignment many Spaniards prefer el trabajo (the assignment) if context is clear.

Usually, yes. Nuances:

• informe: standard for reports (work, academic, technical).
• trabajo: a school/uni assignment (paper/project).
• memoria: often a written report in engineering, research, end-of-year summaries.
• ensayo: essay.
• reporte: common in Latin America, rare in Spain.

Use the direct object pronoun lo (because informe is masculine singular):

• Ya lo he terminado. Pronoun placement with compound tenses: before the auxiliary (ya lo he terminado), not between auxiliary and participle and not after the participle. With an infinitive/gerund/affirmative imperative, it can attach:
• Voy a terminarlo / Lo voy a terminar.
• Estoy terminándolo / Lo estoy terminando.
• Termínalo ya.

The usual order is: ya + pronoun(s) + haber + participle.

• Ya lo he terminado. Avoid: Lo ya he terminado or He lo terminado (both incorrect).

Yes. Tener + participio focuses on the result you “have” accomplished: Ya tengo terminado el informe / Tengo el informe terminado. With tener, the participle often agrees with the direct object:

• Tengo terminada la tarea.
• Tengo terminados los informes. This construction highlights a completed result in your possession/responsibility, whereas haber + participio highlights the completion of the action.

Yes, but they sound more formal/bureaucratic:

• He concluido mi informe.
• He finalizado mi informe.
• He completado mi informe. Everyday Spanish in Spain more often uses terminar or acabar.

Use terminar de + infinitive to say you finished doing an activity:

• He terminado de escribir mi informe. (finished writing) Use a direct object when the thing finished is a noun:
• He terminado mi informe. With activities, don’t use a direct object: say He terminado de comer, not He terminado la comer.