Learn Hardcore Japanese: watasi ha hassou no yotei wo kakuninsimasu.

は marks the topic: you’re saying “As for me, …”
が marks the subject with focus/contrast. 私が発送の予定を確認します implies “I (as opposed to someone else) will check.”
In a neutral statement like this, 私は is natural if you include a subject at all.

Do I need to say 私 here?

Usually no. Japanese often drops the subject when it’s obvious. 発送の予定を確認します already means “I’ll check the shipping schedule” in most contexts. Use 私は if you need to clarify the agent or contrast with others.

Why does 確認します look like present tense even though it means “will check”?

Japanese “non-past” (〜ます／〜る) covers both present and future. Context decides. If you want to make the timing explicit, add an adverb:

今確認します (I’ll check now)
後で確認します (I’ll check later)
すぐ確認します (I’ll check right away)

What does の do in 発送の予定?

の links nouns: “the plan/schedule of shipping,” i.e., “shipping schedule/plan.” You’ll also see the compound form 発送予定 (dropping の). Both are correct:

発送の予定 feels slightly more explanatory/natural in speech.
発送予定 is a concise compound common in business writing.

Why is を used before 確認します?

を marks the direct object of the verb. 予定を確認します = “(I) check the schedule.” You can switch to は for contrast or topic: 予定は確認します “I will check the schedule (but maybe not other things).”

Is 確認する a verb? How does 確認します work?

確認する is a common “suru-verb” (noun + する). Polite forms:

Dictionary: 確認する
Polite non-past: 確認します
Polite past: 確認しました
Te-form: 確認して
Negative: 確認しません

How is 確認する different from 確かめる or チェックする?

確認する: formal/neutral “to confirm/verify” (common in business).
確かめる: “to make sure,” often implies personally verifying/checking evidence.
チェックする: casual “to check” (everyday speech; less formal than 確認).

Is 発送 the right word here? What about 出荷 or 送付?

発送: sending out items (parcels, orders). Very common for deliveries.
出荷: shipping goods from a manufacturer/warehouse (logistics/wholesale nuance).
送付: sending documents/materials (business/administrative). Pick based on context; for customer orders, 発送 is usually best.

How do I pronounce everything?

私: わたし (watashi)
Particle は is pronounced “wa” here.
発送: はっそう (hassou / hassō) — note the small っ and long ō
の: no
予定: よてい (yotei)
Particle を is pronounced “o.”
確認します: かくにんします (kakunin shimasu)

Is this polite enough for business?

Yes, it’s standard polite. For extra formality/humility when telling a client what you will do:

発送のご予定を確認いたします。
発送予定を確認いたします。 To ask the client to check:
ご確認ください。
ご確認をお願いいたします。

Can I drop particles like は or を?

Dropping 私は is fine; dropping just は while keeping 私 is odd.
を is sometimes omitted in casual speech, but in writing and business it should be kept: 予定を確認します.

Can I change the word order?

Modifiers must come before what they modify, and the verb typically comes last.

Natural: 私は発送の予定を確認します。
With emphasis: 発送の予定は私が確認します。
Also okay as a nominalization: 発送予定の確認をします。
Unnatural: moving pieces inside the 発送の予定 chunk or placing the verb mid-sentence.

What’s the difference between 予定 and スケジュール?

予定: plan/arrangement; broad and common.
スケジュール: schedule/timetable; often implies specific time slots. In logistics, 発送スケジュール is also common. Both are fine; pick what fits your company style.

How do I make it past, negative, or a question?

Past: 発送の予定を確認しました。
Negative: 発送の予定を確認しません。
Past negative: 発送の予定を確認しませんでした。
Question: add か → 発送の予定を確認しますか。 (Past question: 確認しましたか。)

How can I say “I’ll check now/soon/later”?

今確認します。 (now)
すぐ確認します。 (right away)
後で確認します。 (later)

Is it okay to write everything in kana?

It’s readable as わたしははっそうのよていをかくにんします, but in normal adult/business writing you should use the kanji (発送・予定・確認). Kanji improves clarity and looks professional.